Innovation, research and development for the improvement of motor output power are one of the major concerns since the beginning of the development of motors. Generally, the improvement of the motor output power may be realized by directly increasing the motor specifications. However, a higher motor output power may lead to a heavier motor weight and a larger motor size, and the way for increasing the motor output power directly through the increase of motor specifications may not suitable for some living supplies or industrial equipments. Thus, for those ordinarily skilled in the art, it is an important object to develop a motor with higher power conversion efficiency.